Among the scores of young militants who came to visit him in London was the chief suspect in the Madrid train bombings.

His followers also included Richard Reid, the shoe bomber.

A ruling by the Special Immigrations Appeals Commission revealed that there was evidence to show that Abu Qatada “has been concerned in the instigation of acts of international terrorism”.

MI5 agents held meetings with the cleric.

He disappeared from his family home in West London just before the UK's terror law came into force.

Indignant French officials accused MI5 of helping the cleric to abscond. While he remained on the run, one intelligence chief in Paris was quoted as saying: “British intelligence is saying they have no idea where he is, but we know where he is and, if we know, I’m quite sure they do.”

Almost a year later Abu Qatada was found hiding in a flat not far from Scotland Yard.

Mr Justice Collins ruled that the cleric was “at the centre in the UK of terrorist activities associated with al-Qaeda”.

He is a Jordanian national who arrived here with a forged United Arab Emirates passport in September 1993 claiming asylum.

Jordan told Britain that he had been convicted for terrorist attacks in Amman seven months before September 11.

Spanish investigators produced evidence that a militant they had in custody in Madrid — Abu Dahdah — had visited the cleric more than 25 times, bringing him money and new recruits.

In the letter, seen by The Independent on Sunday, Mr al-Rawi alleges that:

* He was recruited by MI5 weeks after 11 September and was in contact with Abu Qatada.

* MI5 always knew where Abu Qatada was hiding after he fled his home in west London hours before new powers to detain suspects without charge came into force in December 2001. He lived at Elephant & Castle, close to MI5's headquarters, for nine months before being arrested.

* Throughout this time, Mr al-Rawi had 'numerous' meetings with three MI5 agents - 'Alex', 'Matthew' and 'Martin' - in hotels and bars in London, passingmessages between them and Abu Qatada.

* After Mr al-Rawi expressed anxieties his safety was at risk from his contacts with MI5, a service lawyer "assured" him that it would "aid him in his defence [and] would appear as witnesses on his behalf".